hmukos wrote: ↑20 May 2020, 09:16
I don't understand how does scanout speed affect the Min Max input lag cases for "VSYNC OFF 2000fps @ 60hz" if frame scanout happens at the same time the frame was rendered regardless of refresh rate.
Because we're not counting all the tearlines sequentially from top to bottom within a single scanout, only the one triggered by the input, which, with V-SYNC off, could be anywhere on-screen. So since 60Hz has a 16.6ms scanout, it has a 16.6ms min/max range when testing V-SYNC off like this, whereas 240Hz only has a 4.2ms min/max range.
Have you seen an actual video of the scanout on an LCD display?
The individual "sweeps" from top to bottom (which contain all possible tearlines per cycle) at 60Hz are slower than they are at higher refresh rates, so if my click happens to register when the current scanout just started, and it ultimately reflects in the scanout 1, 2, or 3 (what have you) after it, the tearline could appear at the top, middle or bottom of the display.
If it appears at the bottom @60Hz, it's potentially up to 16.6ms slower than a tearline occurring closer to the top of the screen in that same scanout because you're eyeballs simply aren't going to see that tearline occur until the scanout is nearly complete, and regardless of framerate, sync or no sync, a single 60Hz scanout cycle takes 16.6ms. It's as simple as that.
Also, I will note I was measuring the differences between scenarios at the same refresh rate (per) here, not the base input lag numbers themselves, because that will vary depending on the given test equipment:
https://blurbusters.com/gsync/gsync101- ... ettings/9/
In fact, at 240Hz, first on-screen reactions became so fast at 1000 FPS and 0 FPS, that the inherit delay in my mouse and display became the bottleneck for minimum measurements.
I'd estimate combined mouse/display delay was up to 12ms. But yes, that still leaves us with a 13ms (nearly 1 frame) difference between min/max @60Hz, which again, scales proportionately with the given refresh rate; 240Hz had a 3ms difference between min/max readings.
hmukos wrote: ↑20 May 2020, 09:16
Yes, I have read it and for G-SYNC+V-SYNC that animation makes a lot of sense to me.
Good, because it's the same thing with V-SYNC off, except the reaction can occur at any point on the display's vertical axis (instead of just the top).